Electrical Test Probe Alignment Aid
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Method of automatically sensing probe alignment errors so that corrections may be made on the fly as a tester steps across a wafer. The probe pattern illustrated is embedded in the design at opposite corners so that axis and rotational errors are sensed. If opposite corners are in registration, it is reasonable to assume that all other pads are in registration. Pad location #1 contains no metal, but is surrounded by metal lands "A", "B", "C" and "D" (captive sensing zone). If the probes are misaligned to the left, then probe #1 contacts metal land "A" which is tied to pad #3. Pad #3 is designed such that even if the probes are misaligned to the left, contact is still made to pad #3. When the probes are set down, the test program checks the continuity between pad #1 and pads #2, #3, #4 and #5.